experiences of Jesus, of God, of the Spirit; but it does not tell us the exact relations of the Three—­how God is related to the Spirit, or Jesus distinct and at the same time one with the Father.  So acute a thinker as Paul never seems to have worked this out.  At one time he compares God’s relation to His Spirit to man’s relation to his spirit ("Who among men knoweth the things of a man, save the spirit of the man which is in him? even so the things of God none knoweth, save the Spirit of God"); and once he identifies the Spirit with the glorified Christ ("The Lord is the Spirit").

But while Paul and other New Testament writers did not feel the need of thinking out what their threefold experience of God implied as to His Being, later Christians did; and using the terms of the current Greek philosophy, they elaborated the conception of three “Persons” in one Godhead.  We have no exact equivalent in English for the Greek word which is translated “person” in this definition.  It is not the same as “a person” for that would give us three gods; nor is it something impersonal, a mode or aspect of God.  It is something in between a personality and a personification.

Let us remember that this doctrine is not in the New Testament, but is an attempt to explain certain experiences that are ascribed in the New Testament to Jesus, the Father, the Holy Spirit.  Even the hardiest thinkers caution us that our knowledge of God is limited to a knowledge of His relations to us:  Augustine says, “the workings of the Trinity are inseparable,” and Calvin, commenting on a passage whose “aim is shortly to sum up all that is lawful for men to know of God,” notes that it is “a description, not of what He is in Himself, but of what He is to us, that our knowledge of Him may stand rather in a lively perception, than in a vain and airy speculation.”  But let us also recall that in this doctrine generations of Christians have conserved indispensable elements in their thought of God:—­His fatherhood, His Self-disclosure in Christ, His spiritual indwelling in the Christian community.  Wherever it has been cast aside, something vitalizing to Christian life has gone with it.  But at present it is not a doctrine of much practical help to many religious people; and it often constitutes a hindrance to Jews and Mohammedans, and to some born within the Church in their endeavor to understand and have fellowship with the Christian God.

We may adopt one of two attitudes towards it:  we may accept it blindly as “a mystery” on the authority of the long centuries of Christian thought, which have used it to express their faith in God—­hardly a Protestant or truly Christian position which bids us “Prove all things; hold fast that which is good”; or we may consider it reverently as the attempt of the Christian Church of the past to interpret its discovery of God as the Father Lord, revealed in Christ, and active within us as the Spirit of love; and use it in so far as